Last night I'm typing away on MS Word in Windows, because that's what we have at work. I don't know what I did, but I went capitalize some letter, and I must've hit the wrong key. The computer gave a message like, "You have locked this computer. Only .....so and so who logged in..... can unlock this AMAZINGLY STUPID FEATURE!" I was sweating bullets. I mean, a good 20 minutes of work, at 2am; you don't want to go losing this. Luckily whoever it was had the same password as their login, so all wasn't lost. Still. Dumb, dumb feature to attach to such an easily typed mistype. Has never happened with my Mac, of course. 
